SIMPLE TUBULAR GLAND
The figure shows an example of a tubular gland. There are millions of small simple tubular glands in the intestinal mucosa, called intestinal crypts or Lieberkühn crypts.
Its tubules produce and secrete mucus and other products. The secretion is released by the tubular cells into the gland lumen and then conducted to the intestinal lumen. Mucus is important for the lubrication of the intestinal mucosa and of the intestinal content.
The tubules are slightly curved and for this reason some may not be seen entirely in one section, but as isolated segments of different lengths.
The tubules are formed by a simple columnar epithelium composed of covering cells and goblet cells that produce and secrete the mucus. In the large intestine the number of goblet cells predominates over that of covering cells. In histological sections the tubular lumen is usually seen empty and therefore unstained.
One complete tubule is seen at the left of the image center. Some of glands are highlighted, their epithelium in dark blue and the gland lumen in light blue with goblet cells highlighted in green. The connective tissue that supports the glands (its lamina propria), highlighted in light brown.
The upper (unstained, “empty”) area of the figure is the intestinal lumen.
Its tubules produce and secrete mucus and other products. The secretion is released by the tubular cells into the gland lumen and then conducted to the intestinal lumen. Mucus is important for the lubrication of the intestinal mucosa and of the intestinal content.
The tubules are slightly curved and for this reason some may not be seen entirely in one section, but as isolated segments of different lengths.
The tubules are formed by a simple columnar epithelium composed of covering cells and goblet cells that produce and secrete the mucus. In the large intestine the number of goblet cells predominates over that of covering cells. In histological sections the tubular lumen is usually seen empty and therefore unstained.
One complete tubule is seen at the left of the image center. Some of glands are highlighted, their epithelium in dark blue and the gland lumen in light blue with goblet cells highlighted in green. The connective tissue that supports the glands (its lamina propria), highlighted in light brown.
The upper (unstained, “empty”) area of the figure is the intestinal lumen.
